2014/12/01 by Oleg I. Siidra, L. P. Vergasova, Yuri L. Kretser +3 · 2 citations
Chemistry · Materials Science · Environmental Science · #Radioactive element chemistry and processing #Crystal Structures and Properties #Thallium and Germanium Studies
paper · doi:10.1180/minmag.2014.078.7.13
openalex publication_date 2014/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/22
Abstract Karpovite, ideally Tl 2 VO(SO 4 ) 2 (H 2 O), was found in a fumarole of the 1st cinder cone of the North Breach of the Great Fissure Tolbachik volcano eruption (1975 –1 976), Kamchatka Peninsula, Russia. Karpovite occurs as bundles of white, needle-like crystals associated with shcherbinaite, pauflerite, bobjonesite, markhininite, evdokimovite and microcrystalline Mg, Al, Fe and Na sulfates. Karpovite is monoclinic, P2 1 , a = 4.6524(4), b = 11.0757(9), c = 9.3876(7) Å , β = 98.353(2)º, V = 478.60(7) Å 3 , Z = 2 (from single-crystal diffraction data). The eight strongest lines of the X-ray powder diffraction pattern are ( I/d/hkl ): 64/4.289/012, 81/4.253/110, 38/3.683/111, 47/3.557/022, 100/3.438/ 21, 52/2.982/013, 59/2.945/112, 54/2.354/132. The chemical composition determined by the electron microprobe analysis is (wt.%) Tl 2 O 61.43, VO 2 11.53, SO 3 23.55, H 2 O 2.61, total 99.12. The empirical formula (calculated on the basis of 10 O a.p.f.u.) is Tl 2.00 V 0.96 S 2.03 O 9 (H 2 O). The simplified formula of karpovite is Tl 2 VO(SO 4 ) 2 (H 2 O), which requires Tl 2 O 61.93, VO 2 12.09, SO 3 23.34, H 2 O 2.62 total 100.00 wt.%. The crystal structure was solved by direct methods and refined to R 1 = 0.026 for 4196 independent observed reflections. The structure contains two symmetrically independent Tl + sites, one V 4+ site and two S 6+ sites. VO 5 H 2 O octahedra and SO 4 tetrahedra link together by sharing corners to form kröhnkite-type stripes parallel to the a axis with their planes oriented parallel to (021) and (02 ). Tl + cations are located between the chains, linked into a three-dimensional structure. The new mineral is named in honour of Professor Gennadii Alexandrovich Karpov (b. 1938), volcanologist at the Institute of Volcanology, Russian Academy of Sciences, Petropavlovsk-Kamchatskii, Kamchatka Peninsula, Russia.